The Earth is almost the shape of a sphere. It is made up of four layers:
- The inner core - This is made from solid nickel and iron. It is in the centre and is the hottest part of the Earth, with temperatures of up to 5,500°C.
- The outer core - This is made from liquid nickel and iron. It surrounds the inner core and is still extremely hot.
- The mantle - This is made up of hot rock called magma, which can flow very slowly. In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt.
- The crust - This is the solid rock outer layer of the Earth.